After two hours of struggle to pump mud into a gas well which blew out Tuesday in southwest China's Chongqing Municipality, emergency teams and technicians finally sealed it off Saturday morning.
Preparations for the capping operation started Friday evening at the gas field. Reporters were ordered to stay at least four kilometers away.
The operation, originally set for 10:00 am Friday, was postponed by one day in order to complete the evacuation of non-essential personnel.
Over 100 medical workers and anti-chemical warfare corps soldiers started a large-scale disinfection of the gas blowout site and eight nearby villages soon after the capping operation was completed Saturday morning.
Samples of plants and water were taken away for examination by the local environmental protection department.
Local people might be allowed to return home within days, after the environment is cleaned and strict protection measures are taken, local officials said.
Meteorologists also expressed optimism.
"Breezes and moderate rain in the next three days will be helpful for preventing the spread of the gas fumes," said Qiao Lin,a senior engineer with the Central Meteorological Station.
"Such weather will also help pollutants sink into the earth in areas near the gas field," Qiao said, but warned that rain would also make soil pollution worse.
With seven more bodies found in nearby areas Saturday, the gas blowout, the worst of its kind in the country, has thus far killed198 people and poisoned over 9,000 others in Kaixian County, some 337 km northeast of Chongqing.
Of the dead, 196 were local villagers who were overcome by toxic fumes, while two were workers at the gas field, according to the rescue headquarters.
But it is feared the toll may rise as further work to search for survivors and identify casualties will be carried out in a more thorough way now that the gas leak has been contained.
More than 42,000 local people were evacuated from their villages after a high concentration of natural gas and sulfureted hydrogen quickly spread to areas within 10 km after the burst on Tuesday night.
As the operation to seal off the well which was the source of the gas burst was completed at 11:00 a.m. Saturday, experts predicted that there would be no new blowout from the capped gas well, operated by the China National Petroleum Corporation.
Meanwhile, 21,600 quilts, 18,000 items of everyday clothing, 11,000 padded overcoats and some 200 tons of food had arrived in the county by Saturday morning, and officials said more relief materials donated from across China are still on the way.
The State Council, China's cabinet, Saturday set up a leading investigation team headed by Wang Xianzheng, director of the State Administration of Work Safety (SAWS), to further investigate the gas well blowout
The members of the investigation team include Chongqing Mayor Wang Hongju, Deputy Minister of Supervision Chen Changzhi and other officials from the Commission for Supervision and Management of State-owned Properties.
The group will submit an investigation report to the State Council after being authorized to find out the cause of the accident, casualties and property losses, and those responsible for the accident.
"It was an accident of rare severity," said SAWS spokesman Huang Yi. "We must learn a lesson from it."
The gas blowout was also the worst work safety accident in China in 2003, according to the SAWS.
SAWS' latest statistics show that work safety accidents kill some 140,000 people on the average every year, causing direct economic losses worth more than 150 billion yuan (18 billion US dollars).